I am going to that is probably not going to be possible given that the dimensions of the two boards are probably not the same and the traces are near impossible to see unless somehow you have magnifying glasses that and very careful hands. The body would not be able to accept it as the screws are most likely in different positions as well as the buttons being slightly off, and even other problems too. As for the screen that would need as different phone shell as well meaning you want to make something custom out of old parts which unless you know how to make a 100% compatible case that does not cause the device to overheat, allows for cellular signal to get through, and can accommodate the type of screen you want with it fitting an accurate and precise measurement that only machines can do. You are best out of luck.
Any smells that come from the phone mean that their is a risk of fire and even worse, the smoke will be filled particulates from products such as lead, copper, lithium, cobalt, plastics, and even other harmful substances. It is dangerous when it snaps as that means the air will be filled with toxic carcinogens that have been known to lead to various types, breathing problems, and chemical burns if exposed to the smoke and/or fire long enough.
Has the device been exposed to any conditions that differ from normal? If so it probably better to pay for a new computer as it would cost more than the value of the machine for a new board which may have been exposed to water, had contact with metal or a substance after being banged, dropped, or slammed shut, seeing that there is smoke and the battery was not ruined it would be a board problem.
This is probably has something to do with the battery, the battery calibration, or some other issue internally with the phone whether it be software or hardware, and seeing as how the phone would have to be near four years old and batteries in phones are rated mainly for 300 to 500 charge cycles (sometimes a bit more with the manufacturer) it could have to deal with the quality of the battery degrading far more quickly as it has over 2000 cycles by this point.
In this case it would probably be best to get rid of the of the battery as there’s most likely a temperature issue with the battery as not many batteries are copper based but lithium based which does have a tendency to explode and get drained with constant recharging from years of use. Based on what you said something is causing the internal temperature to rise causing the contacts to smolder. I would highly recommend either getting a new battery pack
By the looks of the board and what is possible at all, or ever for that computer. If you want a faster ssd you will have to sacrifice Wi-fi connection for as there is only a SATA connection for a maximum for of what 2.5 SSDs can do currently between 500 Mbps to 550 Mbps. This is recommended under Samsung only theirs also have the highest benchmark scores. If you need to install it there is a video online if you search for this pc and upgrades you can do. With that limitation of having no M.2 slots available that is pretty much it.
Unlike Windows and Linux, Mac Os is not readily available to the public as the others are. As Apple does not license out Mac OS to any other hardware manufacturer, while it is possible to build such a machine, it would be an infringement on Apple as you would be using their proprietary operating system Illegally in a machine that has not been authorized by Apple Inc. They only have security updates and firmware updates for machines that already contain Mac OS X and other forms of it. Remember Apple also uses their own file system that only SOME Linux based machines can understand and is not always compatible with everything on the market. In short building one would be possible, but don't do it. A MacBook pro in other words is just a standard laptop with an Apple logo on it. Only Intel CPU's are used by Apple (circa 2006).
The problem is the button was connected directly to the old power supply and your new external one does not connect to the button. The cable that was connected to it was what would be defined as the switch to turn it on. Since the cable is too short to connect to an external power supply, as of now the Saturn will only turn on and remain on infinitely, unless a different type of switch is put in place. I do not know how to fix that issue, but because of this new supply, and the button not controlling directly from the Saturn's mainboard the only thing that can be done is plugging and un-plugging it when not in use.
The only answer I can come up with at this time is that either the wi-fi adapter within your HP device has been damaged, or the antennas have somehow become disconnected (or damaged) it is a common problem within mobile devices. I would recommend that someone look at your device. Remember the Wi-Fi Antennas for all Laptop devices run around the laptop screen in the area where the bezel is. It is also possible that if they had to open your laptop to and disconnect things from within they could have forgotten to reconnect everything.
I had this problem with my Galaxy S8. Did you get anything on the slot? If so clean it a bit. Avoid getting it on the plastic rails. Sometimes the tray will just get stuck and you have to pull a pit your self the pin does not do all the work.